Numerical investigation of an innovative hybrid steel-cross laminated timber wall system

This study investigates the lateral performance and load-sharing mechanism of semi-rigid steel frames infilled with cross-laminated timber (CLT) shear walls. The hybrid wall employs double-web top-and-seat angle connections at the beam–column joints and replaceable annular dampers between the CLT panels and the surrounding steel frame, providing efficient energy dissipation while ensuring that the key dissipative components remain replaceable after seismic damage. Finite element models of the hybrid walls were developed in OpenSees and validated against tests of an empty semi-rigid steel frame specimen and steel–CLT hybrid wall specimens. The validated models were utilized to investigate the lateral load distribution and evaluate the effects of connector strength, frame–wall gap width, semi-rigid joint strength, and connector configuration on the lateral resistance and shear force contribution. The results demonstrate that incorporating CLT shear walls significantly enhances the lateral resistance of semi-rigid steel frames. At 1.9% drift, frame-wall contact rapidly increased lateral stiffness and the CLT shear contribution. At 2.0% drift, the steel frame provided less than 40% of total lateral resistance, making the CLT wall the dominant lateral-load-resisting component. Increasing energy-dissipating connector strength enhanced both peak capacity and CLT shear contribution. Three energy-dissipating connectors per wall side produced the best lateral performance among the configurations examined. Moreover, a 10 mm frame–wall gap achieved a favorable balance among lateral capacity, shear force distribution, construction feasibility, and structural ductility. These results support the seismic design and optimization of steel–CLT hybrid wall systems.